---
title: "allowMessageSendForSession(_:completion:)"
framework: mailkit
role: symbol
role_heading: Instance Method
path: "mailkit/mecomposesessionhandler/allowmessagesendforsession(_:completion:)"
---

# allowMessageSendForSession(_:completion:)

Confirms that the message is ready for delivery.

## Declaration

```swift
optional func allowMessageSendForSession(_ session: MEComposeSession, completion: @escaping ((any Error)?) -> Void)
```

```swift
optional func allowMessageSendForSession(_ session: MEComposeSession) async throws
```

## Parameters

- `session`: The session that represents the properties of the message in the compose window.
- `completion`: A block you call after determining if the message is ready for delivery.

## Discussion

Discussion important: You can call this method from synchronous code using a completion handler, as shown on this page, or you can call it as an asynchronous method that has the following declaration: optional func allowMessageSendForSession(_ session: MEComposeSession) async throws For information about concurrency and asynchronous code in Swift, see Calling Objective-C APIs Asynchronously. MailKit gives your compose session handler an opportunity to confirm that a message is ready for delivery. If the message is ready for delivery and needs no further attention, call the completion handler and pass nil. If there’s an issue with the message’s content and you want to prompt the user, call the completion handler and pass an error that contains a localized description of the reason the message isn’t ready. For example, the following code calls the completion handler with an error if a recipient uses the domain @example.com. enum ComposeSessionError: LocalizedError {     case invalidRecipientDomain          var errorDescription: String? {         switch self {         case .invalidRecipientDomain:             return "example.com is not a valid recipient domain"         }     } }

func allowMessageSendForSession(_ session: MEComposeSession, completion: @escaping (Error?) -> Void) {     // Confirm none of the recipients use @example.com.     if session.mailMessage.allRecipientAddresses.contains(where: { $0.hasSuffix("@example.com")}) {         completion(ComposeSessionError.invalidRecipientDomain)     } else {         completion(nil)     } } note: The alert that the system displays to the user is advisory only. The user can choose to send the message regardless of the issue your compose session handler indicates.